Examination of the tissues of lower vertebrate teeth provides a link between preserved tissues of fossil forms and the dynamic structure and function of tissues of living animals. The current research continues to examine experimentally tooth and root formation occurring in teeth with different types of attachments to the underlying jaw (fibrous, hinged, ankylosed, and socketed). An important component of the research is the continuing search for new animal models for tooth and jaw regeneraton and transplantation studies, especially those of amphibians. During the coming project period research emphasis will shift from analysis by scanning electron microscopy (SEM) of anorganic tooth preparations to the relationship of the soft tissues to the hard in the attachment area by SEM supplemented with TEM (transmission electron microscopy) and light microscopy. This will be particularly evident in further examination of the outer surface of the root or pedistal of the Frog tooth. This outer dentin area undergoes a secondary mineralization after the bulk of the tooth is formed and contributes to a distinct changing appearance with age of the tooth. This feature can be of importance in comparing fossil forms as well as a model for clinical problems relating to remineralization of tooth surfaces. Further transplant studies are contemplated in order to compare the behavior and fate of teeth attaching to cellular (Catfish) and acellular (Sunfish) boned fish. Using normal and demineralized preparations the nature of the bone to the success of the transplants will be examined. In a related study, a followup of SEM studies of anorganic preparations of tooth transplants and jaw regeneration will be completed by studying the soft tissue aspects of oral cavity wound healing as well as the healing of tooth transplants, regenerating jaw wounds, and regenerating teeth.